A battery cell has been proposed as a clean, efficient and environmentally responsible power source for electric vehicles and various other applications. One type of battery cell is known as the lithium-ion battery. The lithium-ion battery is rechargeable and can be formed into a wide variety of shapes and sizes so as to efficiently fill available space in electric vehicles. For example, the battery cell may be prismatic in shape to facilitate a stacking of the battery cells. A plurality of individual battery cells can be provided in a battery to provide an amount of power sufficient to operate electric vehicles.
Typical prismatic battery cells have a pair of plastic coated metal layers fused around a periphery of the battery cell in order to seal the battery cell components. The sealing of the battery cells generally begins with providing one of the plastic coated metal layers with a cavity, sometimes called a “butter dish” shape. The battery cell components are disposed inside the cavity of the plastic coated metal layer. The other of the plastic coated metal layers is then placed on top of the battery cell components and fused at the periphery to the one of the plastic coated metal layers with the cavity, for example, by heat sealing around the edges. Before finalizing the sealing, the cell is evacuated. The battery cell for incorporation in the battery is thereby provided.
Battery cells such as lithium-ion battery cells are known to expand and contract during operation and as a result of a charge cycle when recharging. Repeated cycles of expansion and contraction can impact the long term operation of lithium-ion batteries. It has been known to insert polymeric foam expansion units between individual battery cells of the battery in order to accommodate the expansion and contraction of the battery cells in operation, minimize an impact of the expansion and contraction on durability of the battery, and compensate for any manufacturing and assembly tolerances. Cell frames have also been employed to hold together the battery cells and the expansion units. However, known cell frames have undesirably consisted of individual parts that are manufactured and handled separately prior to assembly.
There is a continuing need for a means for mechanically holding and protecting battery cells and expansion units, which provides electrical insulation of the battery cells and permits an installation of the battery cells and expansion units into a battery as a battery cell assembly. Desirably, the means is a one-piece monolithic component that minimizes a complexity of manufacturing, handling, and assembling of the battery.